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Frame thread sizes help

4K views 22 replies 8 participants last post by  pinkwaferwalrus 
#1 ·
Just got the frame back on my 65 Bonneville after powder coating and need to re-cut some of the threads. Can anyone tell me what the thread sizes are for the holes indicated please. thanks.:grin2:
 

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#2 ·
Here's what the parts book say for my 1969;

Oil Tank Mount
21-1822 / S1822
Bolt
UNF 5/16-24TPI X 1/2 U.H

Fender Bracket Mount
14-0113
Bolt
UNF 5/16-24TPI X 9/16 U.H.

Don't know if they are the same but trying to help.

The positions are exactly the same on my frame but 4 years can make a big difference.

Check your parts book and see if the numbers are the same.
 
#5 ·
Hi,

1 You do not cut new threads. You need a rethreading tap
+1. The existing threads are still there, just full of baked-on powder-coating.

Equip yourself with either a full set of three taps or definitely #2 and #3 and, if you can afford it, a ratchet tap wrench.

Start by turning the the #2 tap in the hole with either your fingers or the tap wrench without any force; the taper of the tap will pick up the harder existing thread in the softer powder-coating and start to clear out the latter. When the #2's gone as far as it can, use the #3 to finish the job. Test with a bolt. :thumb

2 If the holes that are goobered up
For any other threads, read the fastener part number from the parts book and look it up in http://stainlessbits.com/link12.html for the thread.

Bookmark the site 'cos it's more useful than a tenner you didn't know you had 'til you found it. :)

Hth.

Regards,
 
#12 ·
He hit the "." instead of the "/" looks like. I just mounted my tank and the bolt was around a 1/2" or so. Didn't measure it since it was the bolt I unscrewed when removing it.

My threads may be different from the OP's but I doubt the changed the depth of the hole.
 
#18 ·
OK, just found some more that need re-threading/cleaning but can't find them in the parts book . They are threaded holes to receive bolts that secure the hangar plates for the rear footrests - see pic. (No21 in the parts book is a CEI 5/16 but also shows a nut and washer but my frame is threaded?) Any thoughts or help gratefully received. thanks
 

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#23 ·
Thanks all. Not sure what PO was trying to achieve but may just be impressions as Stuart suggests although its on all four holes and appears to to look someone intended them to be threaded. In any event I have left them alone as the holes are a comfortable fit for a bolt through both the frame and the hangar plates. Thanks for the help and advice. :)
 
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